Question

find the sides of rutangle whose perimeter is 42cm and diagonal is 15cm ​

Answer 1

Step-by-step explanation:

Since perimeter = 42, we know that L+W = 21

Since diagonal = 15, we know that L² + W² = 15²

Let's define L as 21-W and make a quadratic equation:

(21-W)² + W² = 15²

441 - 42W + W² + W² = 225

2W² - 42W + 216 = 0

W² - 21W + 108 = 0

(W-9)(W-12) = 0

W = 9 or 12

So the sides are 9 and 12. Perimeter = 2(9+12) = 42 and diagonal = √(9² + 12²) = √225 = 15

Answer 2

Answer:

15

Step-by-step explanation:

since perimeter = 42, we know that L+W = 21

Since diagonal = 15, we know that L² + W² = 15²

Let's define L as 21-W and make a quadratic equation:

(21-W)² + W² = 15²

441 - 42W + W² + W² = 225

2W² - 42W + 216 = 0

W² - 21W + 108 = 0

(W-9)(W-12) = 0

W = 9 or 12

So the sides are 9 and 12. Perimeter = 2(9+12) = 42 and diagonal = √(9² + 12²) = √225 = 15.

Hope it helps